Can subroutines on PLC5/80C be implemented?

Hi,

We have a set of drives with start/stop controls executed in the PLC, for which the following lines in the PLC program is repeated for every drive. Any suggestion to implement this through a subroutine to save the PLC memeory. Thanks in advance.

st cond Dr.run Dr. time out fault St Cmd
---| |-----|/|------|/|-----------------------( )-
St Cmd |
---| |--|


stp cond Dr.run Dr. time out fault Stp Cmd
---| |-----|/|------|/|-----------------------( )-
stp cmd |
---| |--|

st Cmd
---| |---------------------------------------(Timer)
stp cmd |
---| |----|

Tmr DN Reset Time out fault
---| |------|/|----------------------------------( )
T flt |
---| |--|

A PLC5/80 has a relatively large amount of memory. It seems unlikely that you would need to save memory for the kind of logic that you have shown.

Subroutines are indeed possible, and you kan pass parameters back and forth, but only words not bits. See the help tekst for the JSR instruction for more information.

The kind of subroutine that you are looking for, is typical for a Siemens S5 or S7 PLC, the AB PLC5 is different in this and many other ways.

I recommend that you make JSR subroutines, but without passing parameters. Just make simple and straight programming with no indirect adressing or such. The program will be much easier to understand in a hurry. And you will not waste memory for passing the parameters.
Tip: You can use cut-and-paste and search-and-replace to speed up your code writing.